Succeeded with Tensorflow r1.5, r1.6, r1.7 but failed with r1.8

[zhchuu]

Thanks for your elegant tutorial code.
I ran the nf_part1_intro.ipynb, and the results are quite normal with Tensorflow r1.5, r1.6, r1.7. But does not look friendly with r1.8. It can't produce the same result.

Does anyone have a similar problem?